Indication device

ABSTRACT

A display device, in particular a fault display, predominantly for systems of a motor vehicle, is provided wherein, as a rule, there is a display only after an operational shut-down of a respective system occurs or when the motor vehicle is switched off.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a display device for systems, in particular ofa motor vehicle, which generates a warning signal or fault signal whenthere are predefined operating states and/or deviations from a set pointoperating state. These systems have a control device which is connectedupstream of the display device and which stores the previously mentionedwarning signals or fault signals.

Display devices and fault displays are generally customary in motorvehicles such as, for example, brake lining wear displays. In suchdisplays a signalling light or the like is immediately switched onwhenever the thickness of one of the brake linings (or pads) of avehicle service brake drops below a predefined value.

Furthermore, motor vehicles may be equipped with monitoring deviceswhich interrogate the respective operating state or fault signals of themotor vehicle systems which are generally specified, and storecorresponding data over the long term. These data can then be displayedand/or converted into fault signals with a separate interrogation unit.Moreover, when a fault occurs, a display can be activated immediately.Appropriate arrangements are the subject-matter of German Patentdocument DE 32 29 411 A1 (having a counterpart in U.S. Pat. No.5,019,799).

German Patent document DE 31 21 645 C2 discloses computer-aided controlsystems which are used for, among other things, controlling the engineand/or for controlling the ignition of the engine. They are also usedfor monitoring various vehicle systems and, in the process, storingstatus data and fault signals. In this way, the working capacity of thecontrol systems can also be used for diagnostic purposes, i.e. thediagnostic interrogations can be carried out in the intervals betweenthe control measures.

German Patent document DE 39 02 339 A1 relates to the acquisition ofdata in a battery-driven electric vehicle. Here, all the data of thevehicle and of the battery are collected and processed in an informationprocessor and information store, and transmitted from there to a dataevaluation unit.

The German Publication by B. Eberwein, W. Dorks entitled"Onboard--Diagnose--Ein Weg zu hoherer Fahrzeugverfugbarkeit (On boarddiagnostics--a way of improving vehicle availability)" in"nachverkehrs-praxis (local) traffic practice)" No. 9/1995, pages 268 to270, relates generally to the usefulness of automatic diagnostic systemsin vehicles. They enable the maintenance of a fleet of vehicles to besignificantly simplified.

European Patent document EP 0 308 944 A2 describes a fault diagnosticdevice for a vehicle control system. Here, fault messages are stored andrecalled before repair or maintenance work is performed. In thiscontext, EP 0 308 944 A2 treats the problem of preventing faultinformation which is erroneously stored from being displayed. For thispurpose, it is proposed to suppress the display of an item of faultinformation if the fault message is not repeated within a predefinedtime period. However, suppressed fault information can also be displayedagain, in order, for example, to facilitate the diagnostic work of aworkshop. As soon as the vehicle's engine is switched off (via theignition switch), the vehicle control system and the fault diagnosticdevice are shut down.

U.S. Pat. No. 4,447,801 relates to a diagnostic system which, when theignition of a vehicle engine is switched on, illuminates appropriatedisplays if a fault is detected. In this context, mention is made of theproblem wherein a driver typically tends to ignore such warning displaysbecause too many displays are illuminated at the same time. U.S. Pat.No. 4,447,801 proposes various approaches to overcoming this problem:

(1) The warning displays may be generally tested before the vehicle isactivated.

(2) Furthermore, the warning displays can be tested successively beforethe vehicle is activated.

(3) In addition, the warning displays can be switched on simultaneouslyand then successively switched off when the vehicle is activated.

(4) Finally, the warning displays can be activated successively at therequest of the driver.

In each case, the warning displays may relate to status variables whichare independent of the running of the vehicle engine.

There is therefore needed a display device which can advantageouslyavoid unnecessary distractions of the person monitoring the displaydevice or of the driver of a motor vehicle.

These needs are met according to the invention by providing a displaydevice having a control device, connected upstream of the displaydevice, which stores warning signals and fault signals, and at leasttemporarily activates the display device when a switching-off signalwhich is generated when there is an operational shut-down of themonitored system or motor vehicle is received.

The invention is based on the general idea that operational states,which make measures necessary or desirable only after a relatively longdelay, are displayed only when operation is terminated so that, in theexample of a motor vehicle, only signals which are actually importantare displayed to the driver while driving. This takes into account thatit is as a rule desirable to monitor diverse systems and functions in avehicle, but that the associated signal displays may distract the driverif they occur "at the wrong time". At the same time, allowance is madefor the fact that a signal display which occurs continuously may easilybe disregarded by the driver.

In the invention, it is advantageous that the activation of the displaydevice during an operational shut-down particularly ensures thatattention is paid to the display.

The invention provides the advantage that, if necessary, very diversefunctions can be monitored, and signals can then also be generated ifthere is no direct need for action. This is because, owing to theinvention, the signals cannot cause the operator or driver to bedistracted during operation.

This also allows for the fact that a large number of systems are ofredundant configurations so that relatively minor malfunctions ofsubsystems are in themselves negligible, but it should equally well bepossible to detect them so that in each case preventive measures can betaken within an appropriate time frame.

According to one advantageous embodiment of the invention there mayalso, if appropriate, be provision for the display device or faultdisplay to be activated briefly when a corresponding signal occurs, evenwhen the respective system is operating, and to be activated again inthe event of an operational shut-down.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

The single FIGURE shows a schematic block circuit diagram of a displaydevice according to the invention in a motor vehicle.

DETAILED DESCRIPTION OF THE DRAWING

The motor vehicle (which is not shown in detail) has an operationalswitch 1 which is switched on to start a vehicle engine (notillustrated) and is switched off when the vehicle engine is switchedoff. For example, the operational switch 1 activates the ignition of theengine. During the switching-on and switching-off processes, signalswhich differ from one another can be tapped at an output of theoperational switch 1. Furthermore, the motor vehicle has differentsystems 2 and 3 which are switched on and off together with the vehicleengine and generate an appropriate signal when there is a deviation froma set point operating state at an output. The aforesaid signals of theoperating switch 1 and of the systems 2 and 3 are fed to a controldevice 4 which is arranged on the input side of the display device 5.The control device can be, for example, an appropriately programmedmicroprocessor based control unit. This display device has signaltransmitters 6 and 7 which are separately assigned to the systems 2 and3 and are activated by the control device 4.

According to the invention, the control device 4 operates as follows.

As soon as the control device 4 receives a switching-on signal from theoperating switch 1, it activates the signal transmitters 6 and 7 for alimited time so that the operational capability of the signaltransmitters 6 and 7 can be detected.

If one of the systems 2 or 3 deviates from its set point operating stateand feeds a corresponding signal to the control device 4, this signal isstored in a memory 4' by the control device 4.

If appropriate, the control device 4 may then briefly activate thesignal transmitter 6 or 7 for the respective system 2 or 3.

When a switching-off signal of the operating switch 1 is received, thecontrol device 4 can check the memory 4' and, if a signal is storedthere, can activate the respectively assigned signal transmitter 6 or 7at least for a predefined time period.

If appropriate, the actuation of the signal transmitters 6 and 7 afterthe switching-off signal has been received from the operating switch 1does not take place until a switch 8 which has been assigned to thecontrol device 4 and/or the display device 5 is manually activated. Thismay be advantageous in particular if desirable signals are to bedisplayed only for inspection purposes.

The memory 4' can be cleared automatically and/or as desired as soon asthe respective signal has been displayed after the vehicle has stoppedoperating or after the switch 1 has been switched off.

As will be readily understood, the control device 4 can perform theabove operation using software, hardware, or some combination of both.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

What is claimed is:
 1. A display device for a vehicle, comprising:a display device capable of displaying a warning or fault signal when at least one of predefined operating states and deviations from a set point operating state of the vehicle occur; a control device coupled upstream of the display device, said control device including a memory for storing previously occurring warning or fault signals; wherein the control device at least temporarily activates the display device when a switching-off signal generated from an operational shut-down of a monitored system or the vehicle is received.
 2. The display system according to claim 1, wherein the warning signal or fault signal is displayed on the display device briefly without delay.
 3. The display system according to claim 1, wherein the display device includes at least one signal transmitter; andfurther wherein when a vehicle system is switched on or when the vehicle starts, the control device briefly activates at least one of the display device and the signal transmitter.
 4. The display system according to claim 2, wherein the display device includes at least one signal transmitter; andfurther wherein when a vehicle system is switched on or when the vehicle starts, the control device briefly activates at least one of the display device and the signal transmitter.
 5. The display system according to claim 1, wherein the memory in the control device stores signals of the vehicle systems.
 6. The display system according to claim 5, wherein the memory can be cleared when desired.
 7. The display system according to claim 5, wherein the memory can be cleared automatically after at least one of the display device and a respective signal transmitter has been activated.
 8. The display system according to claim 6, wherein the memory can be cleared automatically after at least one of the display device and a respective signal transmitter has been activated.
 9. A display system for a motor vehicle, comprising:a display; a control unit coupled to said display, said control unit receiving inputs from vehicle systems to be monitored; wherein said control device at least temporarily activates the display when a switching-off signal generated from an operational shut-off down of the vehicle system being monitored or the vehicle is received, said display displaying a signal indicative of an operational state of the vehicle system to be monitored.
 10. A software product, comprising:a computer readable medium having stored thereon program code segments that:process signal information from predefined operating states and/or deviations from a set point operating state of a vehicle system; detect an operational shut-down of the vehicle system or the vehicle; and at least temporarily activate a display to provide the signal information when the operational shut-down occurs.
 11. A method for displaying vehicle system information, the method comprising the acts of:storing signal information of predefined operating states and/or deviations from a set point operating state of a vehicle system; detecting an operational shut-down of the vehicle system or the vehicle; and at least temporarily activating a display device when the operational shut-down of the vehicle system or the vehicle is detected.
 12. A vehicle display, comprising:at least one signal indicator which is at least temporarily activated to provide signal information about a vehicle system when an operational shut-down of the vehicle system or the vehicle occurs. 